I Gained a Disciple
I had been a mercenary of some renown. Before I even realized it, people had saddled me with the grandiose moniker of Steel Jade. That was how I managed to climb as high as A-class — a fairly lofty perch in the trade. Most would have set their sights on S-class, the absolute peak of the mercenary world. I retired instead.
It wasn't that I had ever wanted to climb high. I simply hated being powerless. I hated remaining weak. That didn't mean I aspired to become the strongest, either. Being reasonably strong was enough for me. By my own standards, the strange part was that I hadn't retired at B-class. Even B-class was considered a solidly formidable rank. The problem was that I'd formed a few decent bonds along the way, and walking away from them turned out to be harder than expected.
In the end, most of those people either died or retired themselves — and that was when I finally stepped away too.
I had withdrawn to a remote region where people rarely came, living out a quiet hermitage, when it happened.
"…You're serious?"
"I am."
An imperial knight had come calling. Ordinarily, knights looked down on mercenaries — but that only applied to the easy targets, C-class and below. From B-class upward, even a knight had to stay on his toes. From A-class on, most knights didn't dare meet your eyes. On top of that, during my active years I had dueled knights with live steel and racked up a rather lopsided win record, so the man standing before me was observing every last formality of respect.
That didn't make me any less foul-tempered about the whole thing.
He was still an unwelcome guest who had shattered the quiet life I'd sought in retirement, and the message he'd brought with him was every bit as filthy.
"So while I was living out here in seclusion, an oracle came down. They started selecting Hero candidates and placing them as disciples under various masters. And somehow my name ended up on that list?"
"It is a special decree from His Imperial Majesty."
In other words, there was no right of refusal. Fine — I could understand that much. An oracle had descended, and if its contents concerned the Demon King, even I would have thrown myself into a frenzy of activity. But even so…
"Hey. Does that little kid look like a Hero candidate to you?"
"…We have confirmed that she is a person of exceptional talent."
I'd asked a question, and what came back wasn't a real answer.
She's clearly standing outside the lines, though.
The little girl the knight had brought — calling her a Hero candidate and my new disciple — had a look in her eyes that had crossed a boundary no ordinary person ever could. Back in my mercenary days, I couldn't stand watching clueless greenhorns die right in front of me, so I'd taught more than a few of them. That was how I knew. This kid had the kind of vessel that could walk into the mercenary trade bare-handed, with nothing at all, and somehow survive long enough to reach S-class. But none of that changed the fact that the girl standing before me was still a child. A little kid who ought to be at her parents' side, being spoiled rotten with affection…
It was painfully obvious. The emperor, terrified he might die at the Demon King's hands, had simply rounded up every child who showed even a glimmer of potential and was forcing this farce on them. He'd gathered so many that he started parceling them out one by one to anyone classified as a master — and eventually the chain had reached me, someone barely clinging to the bottom rung of that ranking.
Put simply: some old fossil who had spent his entire life gorging on every scrap of power and privilege was so desperate to save his own skin that he was snatching up innocent children who belonged in their parents' arms and putting them through this. It was enough to make anyone sick.
"What's your name?"
"…Sera."
"Sera. That's a good name. I'm Jade. From now on, I'll be your…"
Master? Teacher?
Those words didn't quite fit.
"Guardian."
Yes. That was the right word for it.
Just as I'd expected, the kid had talent.
A genuine genius.
It wasn't that I'd put on rose-tinted glasses just because I was her teacher. When you train a mercenary — more precisely, when you train a mercenary not to die — the single most important thing is to analyze and evaluate their level with cold objectivity. A wrong assessment only gets them killed on the next battlefield.
That principle applied no less to this child. If anything, because she might one day have to face the Demon King himself, I analyzed and evaluated her even more ruthlessly than I ever had with my mercenaries. And even under that scrutiny, the fact of her genius remained unchanged — which was, itself, the proof of it.
But even so…
…It's not enough.
I burned through half of a retirement fund substantial enough that I could have lived out my seclusion in comfort, gathering every scrap of information on the Demon King I could find. The information guilds knew the value of what they peddled and jacked their prices to the moon, and because the Demon King's appearance was such a rare event, the relevant materials were scarce enough that money was the only way to get them. After wrangling with those guild rats, haggling them down by the collar, and piecing together every halfway credible document I could find, the conclusion was clear.
No matter how much of a genius the kid was…
Defeating the Demon King was beyond her.
The Demon King was, quite literally, a monster among monsters — something humanity simply could not handle. A being that transcended human limits so completely that nothing could be done about it. Not even an ordinary Sword Master could stand against him. With an ordinary human body… by ordinary means… the Demon King could never be defeated.
Sera was a genius. I had seen countless superhumans on the battlefield, and she was a genius who did not fall short of them. But even so, Sera had a limit. The limit of time. According to the oracle, in the not-too-distant future the Demon King and his armies would appear in the human realm. The odds of Sera reaching the realm of superhumans by then were vanishingly small — and a child who hadn't even reached that realm had no chance of surviving a battle with the Demon King.
"Hah! Hah!"
Today, as always, Sera swung her sword with everything she had. But as her teacher, I knew the truth. There was nothing in this child's blade. No will to live, no dream of a future, not even a scrap of hope for tomorrow. Not a trace. Not a lingering afterimage. Just sharp and hollow, like a cold knife.
A child should never have eyes like these. Should never swing a sword like this.
But even as her teacher, I hadn't been given enough time to do much for her. The window in which I could influence this child was so brief that, years from now, she might look back and think, Oh. Did I ever have someone I could call a teacher? — and that wouldn't even be strange.
The reason this kid can't be a kid is that there were no proper adults around her.
Just as no one despairs because they want to despair, and no one resigns themselves because they want to give up, a child does not stop being a child by choice. It simply happens because there is no other way. Which meant there had been no proper adult nearby to protect her. And now the state had slapped a Hero candidate label on her and was forcing that same child to fight.
…Disgusting.
I had withdrawn from the world and gone into seclusion precisely because I never wanted to see this kind of thing again. Or was this divine punishment for wanting to be comfortable alone? Either way, the fact remained: I was this kid's guardian now.
So I would take the responsibility that came with it.
That was what being an adult meant.
Just because the world was overflowing with garbage instead of proper adults didn't mean I was free to stop being one myself.
I was this kid's guardian.
"What I'm about to do for you is a secret technique of my family."
A lie. I was an orphan who'd lost both parents. I barely remembered my own name. In times of chaos, people without surnames were common enough. Most who made a bit of money bought themselves a family register and pinned on some respectable-sounding name, but I'd never been interested in that sort of thing. I didn't figure it would change anything that mattered. So the talk of a family technique was purely for the benefit of a kid who still didn't know how the world worked. …Saying it like that makes it sound like I'm about to do something terrible to her. When really, I was trying to give her an extraordinary gift.
"So drink this, sleep for a bit, and when you wake up, it'll be done."
"…Yes."
As always, the kid took the sleeping draught I'd prepared with that same blank expression and drained it without a word, then fell asleep. It wasn't trust that let her do this. She simply no longer cared what happened to her.
For this child, reality couldn't have been all that different from hell. There was no other way she could have lost so many of the things a human being was supposed to have. I didn't want to know what had happened to her. Knowing wouldn't let me do anything about it, and I couldn't go back in time and undo whatever had been done to her. So I would simply give her what I could. How she used it would be entirely up to her will and her judgment.
As an inadequate adult, I was merely doing the little I could for a child who had been forced to carry far too much.
That was all this was.
Sera was exhausted.
Sera was horrified.
Sera had given up.
There had been a time, at the beginning, when she burned with something like a sense of mission. But after dying again and again under the name of failure… eventually, nothing remained.
She was a regressor.
No matter how wretchedly she died, no matter how thoroughly she was betrayed, no matter how catastrophic the failure — every time she died, she returned to the moment she was selected as a Hero candidate. At first she had thought it a blessing. Only after repeating death and regression so many times that she stopped counting did she understand it was a curse.
With each cycle of experience, she learned how to grow stronger as quickly as possible. Through countless lives, she mapped out every path through the Demon King's armies. She came to know, in exhaustive detail, which people would betray humanity for their own desires and side with the Demon King.
And still…
She failed, died, and regressed.
The Demon King.
No matter how much experience she accumulated, she could never find a way to defeat that monster. No matter how favorable she made the circumstances, no matter how strong she became, no matter how powerful the allies she gathered — before the Demon King's absurd, overwhelming might, everything turned to nothing. Everything became meaningless.
In the end, she resigned herself.
If there was any possibility at all…
It's impossible unless I have two Aura Hearts in my body…
And not just any Aura Heart. It would have to belong to someone who had at least reached the ranks of a master, even if not quite the realm of superhumans. But that was absurd. Reaching the ranks of a master meant a lifetime spent building one's martial path to that height. An entire life was contained in it. Who would hand that over just because some little girl asked?
Of course, she was no longer the pure-hearted Hero aspirant who had once dreamed so innocently. She was a veteran Hero who would stop at nothing to achieve her goal. So she had considered taking one by force. But she quickly realized that a damaged Aura Heart would only become poison in her body, and so she never even tried.
And so she was condemned to endless failure and regression. No one ever gave her an Aura Heart. Some took the request as an insult and cut off her head on the spot. Others pretended to listen, used her, and discarded her when she was no longer useful. She simply repeated that hellish infinite loop like a machine. If she kept going long enough, surely someone would eventually hand one over… wouldn't they?
But…
She was still human, and eventually her limit arrived.
She began to think that nothing mattered anymore, whatever happened.
She was so worn down that she would simply sleep her days away, then burn to death in the Demon King's fire or die on a demon soldier's blade.
There was no will left in her at all.
Perhaps that essential emptiness had begun to show on the surface — because this time, instead of being entrusted to superhumans as an outstanding candidate the way she always had been, she was placed under an A-class mercenary. He had certainly reached the ranks of a master, but the problem was that he was a mercenary. She had dealt with countless mercenaries. They were the sort who would do anything for money, who would casually betray humanity and join the Demon King's army without a second thought. Expecting anything from a mercenary was as pointless as anything could be. That was the single truth she had learned from every mercenary she had ever known.
But this mercenary named Jade was different. The mercenaries she had known used "training" as an excuse to vent their own frustrations through violence. He never once raised a hand against her. He simply taught her, calmly and steadily. And within that teaching, she could sense a kindness — a genuine wish that his disciple not die. An ordinary person might never have noticed, but Sera, with her countless lifetimes of experience, felt it easily.
Was it because of that kindness?
In front of him, she at least went through the motions.
To his eyes, it probably looked as though a child was keeping up remarkably well. But by her standards, it was nothing more than going through the motions. Even that much, given her apparent age, would have been enough to classify her as a genius — but still.
For her, this stretch of time felt like a rare bit of idle amusement. What kind of end awaited her this time? She was still so thoroughly resigned that she could even entertain thoughts like that.
Then one day, it happened.
Jade suddenly brought her a decoction of herbs steeped with a powerful sleeping agent. Even a full-grown adult would have fallen asleep the moment they drank it. Sera had experienced this scenario countless times. Someone she had believed was a good person turned out to have ulterior motives. Of all the tragedies she had endured across her madly long cycles of regression, that was the one she had lived through most often. So she wasn't even surprised. At least I thought I'd die to the Demon King or his army… With that thought, she drained the decoction. Then she pretended to sleep.
The instant she swallowed it, she used every scrap of her aura to neutralize the drug completely. Then she feigned sleep so perfectly that even someone in the realm of superhumans wouldn't have noticed. No matter how many times she had been stabbed in the back, pain was still pain. She simply wanted to know what this man was after.
"Definitely asleep. That sleeping face is pure angel. She's going to make a lot of men cry someday."
For Sera, it was only a source of trouble. That face had dragged her into every kind of disaster and gotten her killed more than once. There had even been scum who betrayed humanity and joined the Demon King's army just to claim her for themselves, committing every kind of atrocity in the process… A few times she had burned her own face with fire. But after enough regressions, she learned that only created a different set of problems, and she stopped.
"A kid ought to have a kid's face. Tch. Just how badly must the adults around her have failed at being adults… Sigh."
Just as Sera was concluding that putting her to sleep hadn't been for any dark ulterior motive—
In that moment,
Sera felt a searing heat in her lower abdomen.
And at the same time…
"Khack! Ugh… Hah. Hah. Good — none of it got on the kid."
…Something unbelievable was happening in reality.
A burning heat bloomed in her lower abdomen, and at the same instant Jade coughed up blood.
With the experience and knowledge of countless regressions, Sera understood what was happening without any difficulty.
Jade's Aura Heart is being transplanted into me…
The very thing she had struggled so desperately to obtain, across so many lives, was falling into her hands without any effort at all. She could only stare, dumbfounded, at this impossible reality.
"Kid… This world is filthy and cruel. I've shed tears of blood and despaired more times than I can count. But even so — you've still got a long life ahead of you, don't you? You can't go around looking like you've already lived the whole thing. No. Absolutely not. That's the kind of thing you get to do as much as you want once you're a grown-up. A kid just needs to smile and live with hope, the way a kid should."
The hand that stroked her hair as he spoke was impossibly gentle and warm.
It was
the warmth of a person — so warm, so tender, so sweet — that Sera had forgotten for far too long.
And so, without even realizing it, she began to cry.
"Oh no. Having a nightmare? Khack! Must be from forcing you to sleep with medicine. I should've just done it while you were already asleep…? Ugh! Khack!"
Even as he coughed up blood, her teacher fretted over his disciple — and the feelings that rose in her then were beyond any words she could find.